Wireless communication systems are widely used to provide voice and data services for multiple users using a variety of access terminals such as cellular telephones, laptop computers and various multimedia devices. Such communications systems can encompass local area networks, such as IEEE 801.11 networks, cellular telephone and/or mobile broadband networks. The communication system can use a one or more multiple access techniques, such as Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA) and others. Mobile broadband networks can conform to a number of system types or partnerships such as, General Packet Radio Service (GPRS), 3rd-Generation standards (3G), Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunications System (UMTS), the 3rd Generation Partnership Project (3GPP), Evolution-Data Optimized EV-DO, or Long Term Evolution (LTE).
Some wireless communication systems, such as LTE, use orthogonal frequency division multiple access (OFDMA) to for physical layer signaling. By sending data over many carriers using a relatively long symbol duration, and by using multiple-input multiple-output (MIMO) techniques that use multi-output transmitters, satisfactory performance is achievable in a multipath environment. In such systems, a portion of the data transmitted from the base station to wireless user device is devoted to pilot tones and reference signals used by the wireless user device to model the wireless channel so that the wireless used device can effectively receive and decode the transmission from the base station.